Pushbutton switch assembly



Dec. 23, 1969 w. e. PAIGE PUSHBUTTON SWITCH ASSEMBLY Filed Jan. 17.

4 Sheets-Sheet 2 INVENTOR. M1752 fi'fi/FF/A/ 194/55 BY Dec. 23, 1969 w PA|GEI 3,486,145

PUSHBUTTON SWITCH ASSEMBLY Filed Jan. 1'7, 1968 .4 Sheets-Sheet 3 X4 M if M ii I I I INVENTOR.

Dec. w G pA|GE PUSHBUTTON SWITCH ASSEMBLY .4 Sheets-Sheet 4.

Filed Jan. 17, 1968 I NVENTOR. 1 W176? flew/M 24/05 M ,1 1% yrma/EK;

United States Patent US. or. 335--2 06 22 Claims ABSTRACT OF THE DISCLOSURE An array of pushbuttons is mounted on the front of a display panel. A sheet of elastic material having integral spring leaves in register with the pushbuttons of the array is mounted on the back of the display panel. A circuit board on which switches corresponding to the pushbuttons are mounted is supported in spaced relationship from the back of the display panel. When a pushbutton is depressed, it deflects the corresponding spring leaf toward the switch, thereby actuating it. Specifically, the switches are of the magnetic reed type and the spring leaves each carry a permanent magnet that attracts the reeds into contact when it is brought near the switch. Shields for the magnets are formed from a single magnetic sheet that is mounted between the spring leaf sheet and the display panel. The pushbuttons are shaped to lock into permanent nonrotating engagement with the spring leaves. The pushbuttons, are translucent. Lamps are mounted on the circuit board directly behind the pushbuttons. When a pushbutton is depressed, it actuates circuitry that energizes the corresponding lamp until some function is executed. The energized lamps illuminate the corresponding pushbuttons to form a display on the front of the panel.

BACKGROUND OF THE INVENTION This invention relates to switch assemblies and, more particularly, to a component arrangement that is especially well suited for a large pushbutton array.

Applications arise in industry for large arrays of pushbuttons to enable a human operator to control the functioning of equipment manually. An example of such an application is the maintenance panel of a digital computer. Upon the occurrence of a malfunction, a human operator may be called upon to select one of hundreds of different courses of action by depressing the appropriate pushbutton. In general, the pushbuttons in the array are packed as closely as possible on the panel to conserve space. The labor involved in constructing and assembling the parts of a large pushbutton array can become astronomical, due in large measure to the small parts that result from packing the pushbuttons so close together on the panel. The labor required to complete each pushbutton of the array and its associated components must be repeated possibly hundreds of times depending upon the size of the array.

In the case of purely electrical circuitry as distinguished from electromechanical circuitry, such as a manually actuated switch, the use of circuit boards and the techniques for their fabrication and for mounting components thereon have greatly reduced labor costs. In large measure the operations involved in the fabrication of circuit boards can be automated by use of techniques such as wave soldering. These techniques, however, have not been found to be very compatible in general with conventional pushbutton switch structure.

SUMMARY OF THE INVENTION A feature of the invention is the provision of a circuit board on which switches are mounted for use in connection with a pushbutton array. Specifically, the pushbuttons are mounted on a front panel and the circuit board is supported in spaced relationship from the back of the panel. The switches are mounted on the circuit board behind the corresponding pushbuttons of the array and are each operated responsive to the movement of an actuating member coupled to the corresponding pushbutton. When the pushbutton is depressed, the actuating member is moved, and the switch is operated.

Another feature of the invention is the formation of the actuating members in a unitary structure consisting of a single piece of elastic material. Specifically, spring leaves are formed in a sheet of elastic material in register with the pushbuttons of the array. The sheet of material is mounted on the back of the panel. When a pushbutton is depressed, it engages a spring leaf and deflects the leaf toward the corresponding switch on the circuit board to actuate the switch. Most advantageously, the switches are of the magnetic reed type and the spring leaves carry a permanent magnet that closes the corresponding reed switch as it moves into its vicinity. When the pushbutton is released, it is returned to its initial position by virtue of the elasticity of the leaf. All the leaves in the sheet of material can be formed at once by punch-press or etching techniques.

Shields for the permanent magnets carried by the spring leaves are formed from a single sheet of magnetic material sandwiched between the spring leaf sheet and the back of the panel. The shields comprise legs that extend from the magnetic sheet toward the circuit board and embrace the magnets when their corresponding pushbuttons are not depressed. The shields short circuit the external magnetic field of the magnets when the spring leaves are relaxed, thereby reducing the stray flux in the vicinity of the reed switches and preventing actuation of the switches while the corresponding pushbuttons remain undepressed.

According to another feature of the invention, the pushbuttons are shaped so they are locked into permanent nonrotating engagement with the spring leaves after insertion into a hole in a collar portion of the spring leaf. No parts in addition to the spring leaves and the pushbuttons themselves are employed to establish this permanent engagement.

BRIEF DESCRIPTION OF THE DRAWINGS The features of a specific embodiment of the invention are illustrated in the drawings in which:

FIG. 1 is a side elevation view of an array of pushbuttons mounted on a display panel;

FIGS. 2A and 2B are side elevation views of a sheet of magnetic material from which magnet shields are formed and an enlargment of one pattern of the sheet, respectively;

FIGS. 3A and 3B are side elevation views of a sheet of elastic material from which spring leaves that carry permanent magnets are formed and an enlargement of one pattern of the sheet, respectively;

FIG. 4 is a side elevation view of one of the pushbuttons mounted on the display panel of FIG. 1;

FIG. 5 is a back elevation view of the pushbutton of FIG. 4;

FIG. 6 is a top plan view of the pushbutton of FIG. 4; and

FIG. 7 is a sectional view taken through a portion of the display panel of FIG. 1 to illustrate the construction of a single pushbutton switch of the array.

DESCRIPTION OF A SPECIFIC EMBODIMENT In FIG. 1 the front of a display panel 1 is shown on which an array of pushbuttons 2 is mounted. Pushbuttons 2 extend through holes 3 in display panel 1 (FIG. 7) to the rear of display panel 1. A circuit board 4 is supported in spaced-apart relationship from the rear surface of display panel 1 by spacers such as that designated 5 (FIG. 7). The spacers are secured to display panel 1 and circuit board 4 by screws, such as those designated 6 and 7 respectively. As illustrated in FIG. 1, the bottom of circuit board 4 extends below the bottom of display panel 1 to expose a row of electrical terminals 8. Printed circuitry 9, which is etched on printed circuit board 4, leads to terminals 8. Terminals 8 would be inserted in a connector to establish an electrical connection with the system that the pushbutton switch assembly serves.

In FIGS. 2A and 2B a sheet of magnetic material such as iron is shown. A pattern is cut in sheet 20 for each pushbutton of the array by etching or punch-press techniques. This pattern includes a rectangular hole 21, a leg 22, and a magnet shield having end pieces 23 and 24 connected by a transverse piece 25. After the patterns are formed in sheet 20, leg 22 for each pattern is first bent along a line indicated at 26 to a position substantially perpendicular to the surface of sheet 20. As viewed in FIG. 2B, leg 22 would be bent into the paper. End pieces 23 and 24 are then bent along lines indicated at 27 and 28 so their surfaces are substantially perpendicular to the surface of transverse piece and leg 22. The bends in all the patterns of sheet 20 could be formed in a single operation simultaneously by a die.

In FIGS. 3A and 3B a sheet of elastic metallic material is shown which has a pattern cut in it for each pushbutton of the array. The patterns are arranged in rows and columns and are oriented obliquely. Each pattern has a spring leaf with a deflective portion 41, a collar portion 42, and a magnet carrier portion 43. Collar portion 42 has a rectangular hole 44 into which pushbutton 2 is locked in permanent engagement with collar portion 42. Hole 44 has a semicircular extension 45 the function of which will be described in detail below in connection with FIG. 7. Holes 46 and 47 form a single slot transverse to the length of the spring leaf when the spring leaf is deflected. The slots are off-center from the spring leaves, which makes a more compact pattern arrangement possible. Holes 48 and 49 are located at the corners of the end of carrier portion 43. Thus, a long center tab 50 and short side tabs 51 and 52 are formed at the end of carrier portion 43. The patterns in sheet 40 could be formed by etching or punch-press techniques. After the patterns are formel in sheet 40, carrier portion 43 is bent along a line 53 into the paper as viewed in FIG. 3 until the elastic limit is exceeded and the spring leaf remains permanently deformed along line 53, forming an angle of about degrees with the surface of sheet 40.

Reference is now made to FIGS. 4, 5, and 6 which are various views of one of pushbuttons 2. For the purpose of describing the configuration of the pushbutton, it is divided into four parts along its longitudinal axis 60. The four parts are separated by imaginary lines 61, 62, and 63 in FIG. 4. Pushbuttons 2 are preferably made of Lucite or some other translucent material. An end cap 64 is located to the right of imaginary line 61. A solid cylindrical portion 65 is located between imaginary lines 61 and 62. Cap 64 is cemented to the end of cylindrical portion 65. The part of the pushbutton between imaginary lines 62 and 63 has flat sides 66 and 67 that are parallel to one another and flat sides 68 and 69 that are parallel to one another and perpendicular to sides 66 and 67. Semicylindrical members 70 and 71 are located adjacent sides 68 and 69, respectively. The part of the pushbutton between imaginary lines 62 and 63 is formed from a cylinder with the same diameter as portion 65. In other words, the corners between sides 66, 67, 68, and 69 and the sides of semicylindrical members 70 and 71 are themselves extensions of the cylindrical surface of portion 65 as illustrated in FIG. 5. The part of the pushbutton to the left of imaginary line 63 has flat sides 72 and 73 that are paral- 4. lel to one another and flat sides 74 and 75 that are parallel to one another. Sides 72, 73, 74, and 75 are oriented at an angle of 45 degrees to sides 66, 67, 68, and 69. Sides 72 and 74 are joined by a flat side 76, which lies in the same plane as side 68. Similarly, sides 73 and 75 are joined by a flat side 77, which lies in the same plane as side 69. The part of the pushbutton to the left of imaginary line 63 is also formed from a cylinder with the same diameter as portion 65. Thus, sides '78 and 79, which join sides 73 and 74 and sides 72 and 75, respectively, are extensions of the cylindrical surface of portion 65. As illustrated in FIG. 5, sides 73, 74, and 78 and sides 72, 75, and 79 form noses that protrude substantially beyond surfaces 66 and 67, respectively.

The assembly of sheet 20, display panel 1, circuit board 4, sheet 40, and pushbuttons 2 is now considered. First, sheet 20 is mounted directly against the rear surface of display panel 1 with legs 22 extending in a rearward direction and the centers of holes 21 aligned with the centers of holes 3. In other words, the surface of sheet 20 illustrated in FIG. 2B abuts and faces the rear surface of display panel 1.

Second, sheet 40 is mounted directly against sheet 20 with carrier portions 43 extending in a rearward direction and the centers of holes 44- aligned with the centers of holes 3. In other words, the surface of sheet 40 shown in FIG. 3B abuts and faces sheet 20. Sheet 40 is actually fitted into its final position with sheet 20 by first offsetting sheet 40 with respect to sheet 20 so the transverse slots formed by holes 46 and 47 are aligned with transverse pieces 25 of sheet 20. Sheet 40 is then moved toward sheet 20 until transverse pieces 25 and end pieces 23 and 24 pass through the transverse slots of sheet 40. In so doing, the spring leaves are deflected somewhat to provide sufficient clearance for end pieces 23 and 24. Thereafter, sheet 40 is moved slightly upward and to the left as viewed in FIG. 3B to align carrier portions 43 and legs 22 and to align the centers of holes 44 and 21. Legs 22 extend through the openings in sheet 40 left by carrier portion 43.

Third, a permanent magnet is secured to the end of carrier portion 43 of each leaf spring. In FIG. 7, a permanent magnet 54 is shown that is held between tabs 51 and 52 and tab 50 which could be bent to grip magnet 54 as shown by a die designed for the purpose. Preferably, magnet 54 is also cemented to tabs 50, 51, and 52.

Fourth, circuit board 4 is mounted to the rear of display panel 1 by spacers 5. As illustrated in FIG. 7, sheets 20 and 40 are held between the end of spacers 5 and the rear of display panel 1.

Fifth, pushbuttons 2 are locked into permanent engagement with collar portion 42 of the spring leaves by means of a simple two-step operation. The pushbutton is first inserted through the corresponding hole 3 from the front of display panel 1 and then rotated 45 degrees with respect to collar portion 42. Sides 78 and 79 are aligned with a diagonal of hole 44 as the pushbutton is inserted through hole 3 and hole 44 in collar portion 42. The orientation of hole 44 relative to the pushbutton during insertion is illustrated in FIG. 5 by a dashed outline 80. The part of the pushbutton to the left of imaginary line 63 clears hole 44 when so oriented, but not the parts to the right of line 63. The diagonal of the approximate rectangle formed by sides 66, 67, 68, and 69 is larger than the distance between opposite edges of the hole and smaller than the diagonal distance of the hole. Thus, after insertion and prior to rotation, the pushbutton penetrates to the rear of display panel 1 a distance such that line 63 lies in the plane of hole 44. As the pushbutton is rotated 45 degrees after insertion, the pushbutton snaps into place. The orientation of hole 44 relative to the pushbutton after rotation is illustrated by a dashed outline 81 in FIG. 5. Sides '68 and 69 abut opposite edges of hole 44, thereby preventing rotation of the pushbutton. The distance between the noses including sides 78 and 79 and between semicylindrical members 70 and 71 is greater than the width of hole 44 parallel to its edges, so the pushbutton cannot be pulled or pushed axially out of engagement with the spring leaf after it is once looked in place.

Reference is now made to FIG. 7 for a description of the mode of operation of one pushbutton of the switch assembly. A reed switch 90 having an envelope 91 and normally open contacts 92 is mounted to circuit board 4 at a point in the path of the end of the deflected spring leaf. A lamp 93 is mounted to circuit board 4 at a point directly below pushbutton 2. The depressed position of pushbutton 2 is represented by solid lines and the undepressed position of pushbutton 2 is represented in phantom. The side surfaces of collar portion 42 ride on semicylindrical members 70 and 71. As pushbutton 2 is depressed, members 70 and 71 bear down on collar portion 42, thereby deflecting the spring leaf. The axis about which the spring leaf pivots during deflection is parallel to the cylindrical axis of members 70 and 71. The contact between members 70 and 71 and collar portion 42 is such that the component of force exerted by the spring leaf on pushbutton 2 transverse to axis 60 is minimized. Thus, the axial movement of pushbutton 2 is not bound by hole 3 in display panel 1. The spring leaf deflects until end cap 64 is pushed against the front surface of display panel 1 and magnet 54 is pushed against reed switch 90. As a result, contacts 92 are closed. Extension 45 permits side 79 to clear collar 42 and move forward of the spring leaf as pushbutton 2 is depressed. This is illustrated in FIG. 7. When pushbutton 2 is released, the elasticity of sheet 40 returns the spring leaf to its relaxed position and drives pushbutton 2 frontward to its undepressed position. When the spring leaf is in its relaxed position, magnet 54 lies within the threesided enclosure formed by the shield at the end of leg 22 and its poles are adjacent to end pieces 23 and 24. Consequently, the external magnetic field of magnet 54 is constrained to follow the low reluctance path formed by the shield and insufficient stray flux exists to actuate switch 90. When magnet 54 moves out of the enclosure formed by the shield and approaches switch 90, the shield exerts negligible influence on the external magnetic field. This permits reliable operation of the reed switches even though they are packed closely together on circuit board 4.

As depicted in FIG. 7 for one pushbutton, lamps are mounted on circuit board 4 directly behind all the pushbuttons. When a pushbutton is depressed, the corresponding reed switch establishes an electrical circuit through printed circuitry 9 and terminals 8 to the system the pushbutton switch serves. As a result, circuitry in this system is actuated to initiate some function and to energize the corresponding lamp until the function has been executed. The energized lamps illuminate the corresponding pushbuttons to form on panel 1 a display of the functions of the system in progress at the moment.

What is claimed is:

1. A switch assembly comprising:

a front panel;

a plurality of pushbuttons mounted on the front panel;

a circuit board supported in spaced-apart relationship from the back of the panel;

an actuating member coupled to each pushbutton such that the actuating member is moved when the pushbutton is depressed, the actuating members being spring leaves integral with a sheet of elastic material, a leaf being deflected within its elastic limit by the depression of its pushbutton so as to actuate the corresponding switch and to return its pushbutton to the undepressed position when its pushbutton is released; and

means responsive to the movement of the actuating members when the corresponding pushbuttons are depressed for completing electrical circuits formed on the circuit board.

2. The switch assembly of claim 1, in which the sheet is mounted on the back of the panel.

3. The switch assembly of claim 1, in which the spring leaves include a collar portion with a hole having two parallel substantially straight edges, the pushbuttons pass through the holes to engage the spring leaves, and the pushbuttons have two substantially flat parallel sides in abutment with the straight edges of the hole to prevent rotation of the pushbutton.

4. The switch assembly of claim '1, in which the spring leaves include a collar portion with a hole through it, the pushbuttons pass through the holes to engage the spring leaves, the pushbuttons have a semicylindrical surface that bears against the collar portion, and the spring leaves pivot about an axis parallel to the cylindrical axis of the surface during deflection.

5. The switch assembly of claim 1, in which the spring leaves include a collar portion with a rectangular hole through it, the pushbuttons have an end part with two noses extending from opposite sides, the distance between the noses is less than the diagonal distance of the hole and greater than the distance between opposite edges of the hole, the pushbuttons have an intermediate part adjacent "the end part with first and second flat parallel sides and third and fourth flat parallel sides that are perpendicular to the first and second sides to form an approximate rectangle the diagonal of which is larger than the distance between opposite edges of the hole and smaller than the diagonal distance of the hole, the pushbuttons pass through the holes, the noses are located on one side of the collar portion and oriented parallel to two edges of the hole, the sides of the intermediate part are located within and oriented parallel to the edges of the hole, and the pushbuttons have a surface that bears on the collar portion as the pushbutton is depressed.

6. The switch assembly of claim 5, in which the noses are oriented perpendicular to the axis about which the spring leaf pivots during deflection and the hole through the collar portion has an extension permitting the clearance of one of the noses through the hole as the spring leaf is deflected.

7. The switch assembly of claim '6, in which the hearing surface of the pushbuttons comprises semicylindrical surfaces protruding from the first and second sides of the intermediate part, the spring leaves pivot about an axis parallel to the cylindrical axis of the bearing surface during deflection, and the first and second sides of the intermediate part abut opposite edges of the hole.

8. The switch assembly of claim 1, in which the switch is operated responsive to a magnetic field and a source of a magnetic field is carried by the leaf such that it operates the switch upon deflection of the leaf.

9. The switch assembly of claim 8, in which the source of magnetic field is a permanent magnet fixed to the end of each leaf and the switch is a magnetic reed switch.

10. The switch assembly of claim 9, in which the end of each leaf is bent beyond the elastic limit to form a protrusion pointing toward the circuit board.

11. The switch assembly of claim 9, in which shields for the magnets are formed from a sheet of magnetic material, the shields substantially short-circuiting the external magnetic field of the magnet when the spring leaf is in its relaxed position and exerting negligible influence on the external magnetic field of the magnet when the spring leaf is deflected.

12. The switch assembly of claim 11, in which the sheet of magnetic material is mounted on the back of the panel.

13. The switch assembly of claim 11, in which the shields have a leg protruding from the surface of the sheet, a transverse piece at the end of the leg, and end pieces at the ends of the transverse piece, the end pieces lying adjacent to the poles of the magnet.

14. The switch assembly of claim 9, in which the permanent magnet is fixed to the end of the leaf by tabs bent to grip the magnet.

15. The switch assembly of claim 8, in which the end of each leaf is bent beyond the elastic limit to form a protrusion pointing toward the circuit board.

16. The switch assembly of claim 1, in which the pushbuttons are formed of a material that transmits light and lamps are mounted on the circuit board directly behind the pushbuttons, the lamps being energized responsive to the actuation of the respective switches.

17. A switch assembly comprising:

a front panel;

pushbuttons mounted on one side of the panel;

a sheet of elastic material mounted on the other side of the panel;

leaves formed from the sheet that are engaged and deflected within the elastic limit by the respective pushbuttons when they are depressed, the leaves returning the respective pushbuttons to their underpressed position when the respective pushbuttons are released; and

means responsive to the deflection of the respective leaves for establishing respective electrical circuits.

18. The switch assembly of claim 17, in which a sheet of magnetic material is mounted on the other side of the panel between the sheet of elastic material and the surface of the panel, the end of each leaf is bent beyond the elastic limit to form a protrusion pointing away from the panel, a magnet is mounted on the end of each leaf, and shields for the magnets are formed integral with v the sheet of magnetic material and extend through the openings in the sheet of elastic material left by the bent ends of the leaves.

19. The switch assembly of claim 18, in which the sheet of elastic material has transverse slots sufiiciently large for the magnet shields to pass through the sheet of elastic material.

20. The switch assembly of claim 19, in which the spring leaves are arranged'in straight rows and columns and are oriented obliquely, the transverse slots being off center from the spring leaves. 1

21. The switch assembly of claim 1, in which the means for completing electrical circuits are separate switches mounted on the circuit board, one switch corresponding to each pushbutton.

22. The switch assembly of claim 17, in which the means for establishing respective electrical circuits are switches corresponding to the respective pushbuttons.

BERNARD A. GILHEANY, Primary Examiner R. N. ENVALL, J 11., Assistant Examiner U.S. Cl. X.R.

F- Column 5, line 66' 3 33 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,486,145 Dated December 23', 1970 Inventor(s) Walter Griffin Paige It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

change the conuna to a semicolon; lines 67 through 71, delete a leaf being deflected within its elastic limit by the depression of its pushbutton so as to actuate the corresponding switch and to return its pushbutton to the undepressed position when its pushbutton is released;"; line 75, after "board insert I- a leaf being deflected within its elastic limit by the depression of its pushbutton so as to actuate the corresponding circuit completing means and to returl its pushbutton to the undepressed position when its pushbutton is released-a- Column 6, line 52, change "switch" to --circuit completing means--; line 56, change- "switch" to -circuit completing means--. Column 7, line 10, change "switches" to --circuit completing means- I SIGNED AND SEALED Afloat:

Edward M. Fletcher, It. m, J3.

Attosting Officer n Gamissioner of Patents 

